52 



ONYCHOCRINUS PARVUS, n. Sp. 



Plate IV, Fig. 5, azygous side view. 



Species very small. Calyx rather high, basin shaped; plates 

 smooth; sutures distinct. Column round and composed of 

 moderately long plates near the calyx. 



Basals extend beyond the column, but our specimen is injured 

 at the basals so the exact outlines are not shown. Subradials 

 about half as large as the first radials and nearly as long as 

 wide. One of them is concave on the upper face for the recep- 

 tion of a small azygous plate. The first radials are wider than 

 long and truncated more than half the width for the second 

 plate, which is the first plate in the free arms. The arms bi- 

 furcate on the third plate (or the fourth in the radial series). 

 The arms are round externally and the plates more than half 

 as long as wide; sutures transverse. The first armlet is thrown 

 off from the second plate after the first bifurcation. Only a 

 single azj r gous plate is preserved in our specimen and it is 

 slightly out of place. No regular interradials are preserved. 



This species is so much smaller than any heretofore described 

 that no comparison with any of them is necessary to distin- 

 guish it. 



Found in the Kaskaskia Group, at Shoals, in Martin 

 county, Indiana, and now in the collection of Wm. F. E. Gurley. 



